Some plot details (from a legit source, this person correctly stated that DiCaprio and Page would be in this way before anyone else).
I'll spoiler tag stuff just incase:
* 'Inception' is about dreams. They have figured out a way to enter peoples' dreams.
* The technology to enter dreams is not a machine like in the MAtrix or The Cell. It is something that is injected into the bloodstream. They can carry it in a suitcase. In one scene, they enter a person's dream while on a plane.
* Leo's character plays somewhat of a thief. He dives into people's dreams to extract info for others.
* Murphy's character plays a businessman who is about to take over a company.
* Page's character is part of Leo's team. She is a student in Paris who is the architect of the dreams.
* The plan is to insert an idea into the head of Murphy's character. The idea: To branch the compnay off into smaller companies.
* At one point in the film, Leo's wife convinces him to stay in the dream world, saying "It is better than real life." Leo wants to go back to the real world to be with his children. His wife commits suicide in the dream, thinking she'll return to the real world. When Leo returns to the real world, he is charged with the murder of his wife. He has to flee the country and his children.
* The film will be shot in Paris, Morocco, L.A., and London.